For example, a vehicular head-up display (HUD) has been known as a display device for displaying an image (refer to PTL 1, for example). The head-up display employs so-called augmented reality (AR), and displays a virtual image of an image formed on a movable screen, in a space in front of a windshield of a vehicle. With this configuration, a driver can view information about driving (for example, car navigation information) superimposed on a scene in front of the windshield.